"AKC SCIENCE CLASSES"
CLASS 10 TH (CBSE AND MP BOARD)
CHAPTER 14
SOURCES OF ENERGY
BASIC CONCEPTS
1) A good source of energy is one that is able to provide large amount of work per unit volume or mass, be easily accessible at economical rate and can be easily stored and transported.
2) Conventional sources of energy :- Fossil fuels, kinetic energy of flowing water, potential energy of water at a height, wind energy, bio-mass fuel.
3) Among conventional sources of energy, fossil fuels like coal, petroleum and natural gas are non-renewable sources.
4) Energy of flowing water is utilized to produce electricity on a large scale through building of dams. These are called hydropower plants.
5) In thermal power plants, fossil fuels are burnt to heat-up water to produce steam which in turn runs the turbine to generate electricity.
6) Cow-dung, plants and vegetable waste and sewage etc., together are known as bio-mass. These are decomposed in the absence of oxygen to give bio-gas.
7) Energy harnessed using wind power through use of wind mills in mainly used for doing mechanical work.
8) Energy derived from sun (solar energy), sea (tidal or wave energy), radioactive substances (geothermal energy), radioactive substances (nuclear energy) is considered as non-conventional source of energy. These are also called renewable sources.
9) The solar energy reaching the periphery of the earth's atmosphere is considered to be constant and is called solar constant. It is approximately 1.4 kJ per second per square metre or 1.4kW m⁻².
10) Solar energy in the form of heat is collected through devices such as solar cookers, solar cells and solar heaters.
11) Energy derived from hot spots beneath the earth is called geothermal energy.
12) In a process called nuclear fission, the nuclear of a heavy atom, when bombarded with low energy neutrons, gets split into lighter atoms with the release of tremendous amount of energy. This can be harnessed to generate electricity. This is called nuclear energy.
